A clonal analysis of human peripheral blood lymphocytes displaying natural killer-like activity

Human Fc gamma receptor-bearing lymphocytes and T cells, prepared by sorting peripheral blood lymphocytes using the B73.1 monoclonal antibody, have been cloned by limiting dilution. Although quiescent lymphocytes of either cell type were unresponsive to interleukin 2 (IL 2), following induction with phytohemagglutinin and/or the BSM B lymphoblastoid cell line they could be expanded in IL 2 utilizing a mixed irradiated feeder system. Clones originating from B73.1+ lymphocytes displayed a characteristic large granular lymphocyte (LGL) morphology but were otherwise functionally and phenotypically heterogeneous. Of 36 clones analyzed 19 displayed significant natural killer (NK)-like activity, each clone having a target cell repertoire identical to uncloned NK effectors. Furthermore, only a minority of clones (i.e. 5) displayed significant antibody-dependent cellular cytotoxicity, while levels of lectin-induced cellular cytotoxicity were normally commensurate with a clones level of NK-like activity. No correlation was evident between the phenotype of a clone and its cytotoxic activity since of 12 cytotoxic clones phenotyped, 8 expressed the OKT3 antigen but lacked the B73.1 antigen; 2 lacked the OKT3 antigen but expressed the B73.1 antigen and one lacked both OKT3 and B73.1 antigens. In addition the expression of OKT8 and OKT4 antigens was not in any way predictive of the cytotoxic capacity of a given clone. Several clones expressing T cell associated antigens bore a phenotype that distinguished them from T cell clones insofar as T cell subset antigens were expressed in the absence of the OKT3 antigen and vice versa.(ABSTRACT TRUNCATED AT 250 WORDS)